In the event of earth movement such as that caused by earthquake it is not at all uncommon to have the water line of a house or other building severed from the source of the building's water such as a water main or supply line. If there is a break, the water in the building's water line at that time will immediately begin to drain or siphon therefrom. Within a very short period of time the water line may be completely emptied.
Loss of water from a water line is not merely inconvenient but can create a serious and dangerous situation as well. Days may pass before water service is restored. The occupants of the building in such situations will find themselves without a convenient source of potable water. If water from other sources is available at all it may be unclean or contaminated. Illness or even death can result through use of such water. While people are encouraged to store potable water in containers for possible use in emergency situations it is an unfortunate fact that few persons actually do this.